Control system for work vehicle, control method, and work vehicle

ABSTRACT

A control system for a work vehicle including a work implement comprises a first operating lever, a first operating member, and a controller. The first operating lever is for operating the work implement. The first operating member is provided on the first operating lever. The controller is programmed to control the work implement based on a designed terrain indicating a target shape of a work object. The controller is configured to change a position of the designed terrain in response to an operation of the first operating member when a performance condition is satisfied. The performance condition includes the first operating lever being located in a neutral position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/118,480, which is U.S. National stageapplication of International Application No. PCT/JP2016/061541, filed onApr. 8, 2016. The entire disclosures of U.S. patent application Ser. No.15/118,480 and International Application No. PCT/JP2016/061541 arehereby incorporated herein by reference.

BACKGROUND Field of the Invention

The present invention relates to a control system for a work vehicle, acontrol method and a work vehicle.

Background Information

There has been conventionally a type of control system for a workvehicle that is configured to perform an automatic control of a workimplement. For example, a hydraulic excavator described in Japan PatentNo. 3869792 is configured to control a work implement such that a bucketof the work implement does not excavate the earth across a preliminarilyset designed terrain.

Additionally, the control system for a work vehicle is provided with anoperating member for operating a function of the automatic control. Forexample, the aforementioned hydraulic excavator is provided with anoperating member for changing the position of the designed terrain, andthe operating member is provided on a console box disposed rearward ofan operating lever for a work implement.

SUMMARY

When the operating member for the automatic control is provided on theconsole box as with the aforementioned hydraulic excavator, an operatorof a work vehicle is required to lose hold of the operating lever forthe work implement in order to operate the operating member. Therefore,many motions are required for operating the operating member, andoperating the operating member becomes complicated.

It is an object of the present invention to provide a control system fora work vehicle, a control method and a work vehicle whereby changing theposition of the designed terrain can be accomplished more easily.

A control system for a work vehicle according to a first aspect of thepresent invention includes a first operating lever for a work implement,a first operating member and a controller. The first operating member isprovided on the first operating lever. The controller is configured tocontrol the work implement based on a designed terrain indicating atarget shape of a work object. The controller is configured to change aposition of the designed terrain in response to an operation of thefirst operating member when a performance condition is satisfied, theperformance condition including the first operating lever being locatedin a neutral position.

In the control system for the work vehicle according to the firstaspect, the first operating member is provided on the first operatinglever. With this arrangement, an operator can operate the firstoperating member while holding the first operating lever. Accordingly,the position of the designed terrain can be changed more easily than ifthe first operating member is located on a console box or some otherpart that is separated from the first operating lever.

Additionally, when the first operating member is provided on the firstoperating lever, there is a concern that the first operating lever maybe moved by an erroneous operation during operating the first operatingmember. In this case, there is a possibility that a motion of the workimplement not intended by an operator will be caused when the functionof changing the position of the designed terrain, which is allocated tothe first operating member, is performed such that, simultaneously, thework implement is actuated by operating the first operating lever. Whensuch an unintentional motion is performed, it becomes difficult toperform a construction work with good quality by the automatic control.

In light of this, the control system for the work vehicle according tothe present aspect is configured to perform the function of changing theposition of the designed terrain, which is allocated to the firstoperating member, in response to operating the first operating memberwhen the performance condition is satisfied, i.e., when the firstoperating lever is located in its neutral position. Because of thisconfiguration, even if the first operating lever is moved duringoperation of the first operating member, it is possible to prevent asituation in which the function of changing the position of the designedterrain in response to an operation of the first operating member andthe function of actuating the work implement in response to an operationof the first operating lever are performed simultaneously. In otherwords, the controller is configured not to execute a positional changeof the designed terrain when the operator moves the first operatinglever from its neutral position by an erroneous operation duringchanging the position of the designed terrain by operating the firstoperating member. Likewise, the controller is configured not to executethe positional change of the design terrain when the first operatingmember is erroneously operated during operating the first operatinglever. Accordingly, it is possible to prevent a situation in which theposition of the designed terrain is changed inadvertently or a situationin which the work implement excavates the earth across the designedterrain while the position of the design terrain is being changed.

In a second aspect of the control system, the controller of the controlsystem according to the first aspect may be configured to change theposition of the designed terrain by a predetermined distance in responseto the operation of the first operating member. With this feature, it ispossible to change the position of the designed terrain by thepredetermined distance with a single, quick operation of the firstoperating member.

In a third aspect of the control system, the controller of the controlsystem according to the second aspect may be configured to change theposition of the designed terrain by the prescribed distance once eachtime the first operating member is operated. With this aspect, theposition of the designed terrain can be changed easily and steadily overdistances larger than the predetermined distance by operating the firstoperating member repeatedly.

In a fourth aspect of the control system, the control system accordingto the second aspect may further include an input device connected tothe controller, and the controller may be configured to change thepredetermined distance in response to an operation of the input device.With this aspect, the predetermined distance can be changed to anappropriate value to accommodate a particular work object or thepreference of an operator.

In a fifth aspect of the control system, the controller of the controlsystem according to the second aspect may be configured such that thepredetermined distance is a fixed value. With this aspect, the featureof changing the position of the designed terrain is simplified becausethe predetermined distance cannot be changed. This feature can helpavoid confusion caused by an operator changing the predetermineddistance without informing other operators.

In a sixth aspect of the control system, the control system according tothe first aspect may further include a second operating member and thecontroller may be configured to change the position of the designedterrain upward in response to the operation of the first operatingmember and downward in response to an operation of the second operatingmember. With this aspect, the designed terrain can be easily moved inthe upward and downward directions using the first and second operatingmembers. Thus, the designed terrain can be moved upward and downward ina simple and intuitive way using separate operating members.

In a seventh aspect of the control system, the controller of the controlsystem according to the sixth aspect may be configured to change theposition of the designed terrain upward by a predetermined distance inresponse to the operation of the first operating member, and to changethe position of the designed terrain downward by the predetermineddistance in response to the operation of the second operating member.With this aspect, it is possible to change the position of the designedterrain upward or downward by the predetermined distance with a single,quick operation of the first operating member or the second operatingmember.

In an eighth aspect of the control system, the second operating membermay be provided on the first operating lever. With this aspect, thefirst operating member and the second operating member are both locatedon the same operating lever and can be operated easily by an operatorusing the same hand.

In a ninth aspect of the control system, the control system may beinclude a second operating lever and the second operating member mayprovided on the second operating lever. Also, the performance conditionmay include the second operating lever being located in a neutralposition. With this aspect the first and second operating members can beoperated by an operator using the left and right hands separately. It isalso possible to set different performance conditions for each of thefirst and second operating members.

A method of controlling a work implement of a work vehicle according toan tenth aspect of the invention, includes the steps of: receiving apositional signal indicating a position of a first operating lever forthe work implement; receiving an operating signal indicating operationof a first operating member provided on the first operating lever;determining whether or not a performance condition is satisfied, theperformance condition including the first operating lever being locatedin a neutral position; and changing a position of a designed terrain inresponse to receiving the operating signal when the performancecondition is satisfied, the designed terrain indicating a target shapeof a work object. With this method, positional change of the designedterrain is not performed when the operator moves the first operatinglever from its neutral position by an erroneous operation duringchanging the position of the designed terrain by operating the firstoperating member. Likewise, positional change of the designed terrain isnot performed when the first operating member is erroneously operatedduring operating the first operating lever. Accordingly, it is possibleto prevent a situation in which the position of the designed terrain ischanged inadvertently or a situation in which the work implementexcavates the earth across the designed terrain while the position ofthe design terrain is being changed.

A work vehicle according to a ninth aspect of the invention comprises awork implement, a first operating lever, a first operating member, and acontroller. The first operating lever is for operating the workimplement. The first operating member is provided on the first operatinglever. The controller is programmed to control the work implement basedon a designed terrain indicating a target shape of a work object. Thecontroller is also configured to change a position of the designedterrain in response to an operation of the first operating member when aperformance condition is satisfied, the performance condition includingthe first operating lever being located in a neutral position. With awork vehicle according to this aspect, a positional change of thedesigned terrain is not performed when the operator moves the firstoperating lever from its neutral position by an erroneous operationduring changing the position of the designed terrain by operating thefirst operating member. Likewise, the positional change of the designedterrain is not performed when the first operating member is erroneouslyoperated during operating the first operating lever. Accordingly, it ispossible to prevent a situation in which the position of the designedterrain is changed inadvertently or a situation in which the workimplement excavates the earth across the designed terrain while theposition of the design terrain is being changed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a work vehicle according to an exemplaryembodiment.

FIG. 2 is a block diagram showing a configuration of a control system ofthe work vehicle.

FIG. 3 is a side view of a schematic construction of the work vehicle.

FIG. 4 is a schematic diagram of an exemplary designed terrain.

FIG. 5 is a block diagram of a configuration of a controller.

FIG. 6 is a schematic diagram showing a distance between a workimplement and a designed surface.

FIG. 7 is a diagram showing a velocity control of the work implement ina leveling control.

FIG. 8 is a diagram of an exemplary guidance screen.

FIGS. 9A and 9B are diagrams of a first operating lever.

FIGS. 10A and 10B are diagrams of a second operating lever.

FIG. 11 is a diagram of an exemplary guidance screen in operating anoperating member.

FIG. 12 is a first diagram of an exemplary guidance screen in operatingthe operating member.

FIG. 13 is a second diagram of an exemplary guidance screen in operatingthe operating member.

FIG. 14 is a third diagram of an exemplary guidance screen in operatingthe operating member.

FIG. 15 is a flowchart showing a series of processing steps to beperformed in operating the operating member.

FIG. 16 is a diagram showing a series of motions to be performed by thework implement in an angle maintaining control.

FIG. 17 is a diagram of an exemplary guidance screen in operating theoperating member.

FIG. 18 is a diagram of an exemplary guidance screen in operating theoperating member.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

An exemplary embodiment of the present invention will be hereinafterexplained with reference to drawings. FIG. 1 is a perspective view of awork vehicle 100 according to the exemplary embodiment. In the exemplaryembodiment, the work vehicle 100 is a hydraulic excavator. The workvehicle 100 includes a vehicle body 1 and a work implement 2.

The vehicle body 1 includes a revolving unit 3 and a drive unit 5. Therevolving unit 3 accommodates an engine (to be described), hydraulicpumps (to be described) and so forth. A cab 4 is disposed on therevolving unit 3. The drive unit 5 includes crawler belts 5 a and 5 b,and the work vehicle 100 is configured to travel when the crawler belts5 a and 5 b are circulated.

The work implement 2 is attached to the vehicle body 1. The workimplement 2 includes a boom 6, an arm 7 and a bucket 8. The boom 6 isattached at its base end to the front portion of the vehicle body 1 soas to be capable of being actuated. The arm 7 is attached at its baseend to the tip end of the boom 6 so as to be capable of being actuated.The bucket 8 is attached to the tip end of the arm 7 so as to be capableof being actuated.

It should be noted that the bucket 8 is an exemplary work tool. Any worktool other than the bucket 8 may be attached to the tip end of the arm7.

The work implement 2 includes a boom cylinder 10, an arm cylinder 11 anda bucket cylinder 12. The boom cylinder 10, the arm cylinder 11 and thebucket cylinder 12 are hydraulic cylinders respectively configured to bedriven by hydraulic fluid. The boom cylinder 10 is configured to drivethe boom 6. The arm cylinder 11 is configured to drive the arm 7. Thebucket cylinder 12 is configured to drive the bucket 8.

FIG. 2 is a block diagram of a configuration of a drivetrain 200 and acontrol system 300 in the work vehicle 100. As shown in FIG. 2, thedrivetrain 200 includes an engine 21 and hydraulic pumps 22 and 23.

The hydraulic pumps 22 and 23 are configured to be driven by the engine21 and discharge the hydraulic fluid. The hydraulic fluid dischargedfrom the hydraulic pumps 22 and 23 is configured to be supplied to theboom cylinder 10, the arm cylinder 11 and the bucket cylinder 12.Additionally, the work vehicle 100 includes a revolving motor 24. Therevolving motor 24 is a hydraulic motor and is configured to be drivenby the hydraulic fluid discharged from the hydraulic pumps 22 and 23.The revolving motor 24 is configured to revolve the revolving unit 3.

It should be noted that the two hydraulic pumps 22 and 23 are shown inFIG. 2, but alternatively, only one hydraulic pump may be provided. Therevolving motor 24 is not limited to the hydraulic motor, and may be anelectric motor.

The control system 300 includes an operating device 25, a controller 26and a control valve 27. The operating device 25 is a device foroperating the work implement 2. The operating device 25 is configured toreceive an operation performed by an operator for driving the workimplement 2 and output a positional signal in accordance with the amountof this operation. The operating device 25 includes a first operatinglever 28 and a second operating lever 29.

The first operating lever 28 is provided to be operable in fourdirections, i.e., the right, left, back and forth directions. Two of thefour operating directions of the first operating lever 28 are allocatedto an operation of raising the boom 6 and an operation of lowering theboom 6. The remaining two operating directions of the first operatinglever 28 are allocated to an operation of upwardly tilting the bucket 8and an operation of downwardly tilting the bucket 8.

The second operating lever 29 is provided to be operable in fourdirections, i.e., the right, left, back and forth directions. Two of thefour operating directions of the second operating lever 29 are allocatedto an operation of raising the arm 7 (arm damping operation) and anoperation of lowering the arm 7 (arm excavating operation). Theremaining two operating directions of the second operating lever 29 areallocated to an operation of revolving the revolving unit 3 to the rightand an operation of revolving the revolving unit 3 to the left.

It should be noted that the contents of the operations allocated to thefirst and second operating levers 28 and 29 are not limited to the aboveand may be changed.

The operating device 25 includes a boom operating portion 31 and abucket operating portion 32. The boom operating portion 31 is configuredto output a positional signal in accordance with the operating amount ofthe first operating lever 28 for operating the boom 6 (hereinafterreferred to as “boom operating amount”). The bucket operating portion 32is configured to output a positional signal in accordance with theoperating amount of the first operating lever 28 for operating thebucket 8 (hereinafter referred to as “bucket operating amount”).

The operating device 25 includes an arm operating portion 33 and arevolving motion operating portion 34. The arm operating portion 33 isconfigured to output a positional signal in accordance with theoperating amount of the second operating lever 29 for operating the arm7 (hereinafter referred to as “arm operating amount”). The revolvingmotion operating portion 34 is configured to output a positional signalin accordance with the operating amount of the second operating lever 29for operating the revolving motion of the revolving unit 3. Thepositional signals from the respective operating portions 31 to 34 areinputted into the controller 26.

The controller 26 is programmed to control the work vehicle 100 based onthe obtained information. The controller 26 includes a storage unit 38and a computation unit 35. The storage unit 38 is composed of memories(e.g., RAM and ROM) and an auxiliary storage device. The computationunit 35 is composed of a processing device (e.g., CPU). The controller26 is configured to obtain the positional signals from the boomoperating portion 31, the arm operating portion 33, the bucket operatingportion 32 and the revolving motion operating portion 34. The controller26 is configured to control the control valve 27 based on thesepositional signals.

The control valve 27 is an electromagnetic proportional control valveand is configured to be controlled by a command signal from thecontroller 26. The control valve 27 is disposed between the hydraulicactuators (the boom cylinder 10, the arm cylinder 11, the bucketcylinder 12, the revolving motor 24, etc.) and the hydraulic pumps 22and 23. The control valve 27 is configured to control the flow rates ofthe hydraulic fluid to be supplied from the hydraulic pumps 22 and 23 tothe boom cylinder 10, the arm cylinder 11, the bucket cylinder 12 andthe revolving motor 24.

The controller 26 is configured to control the command signal to betransmitted to the control valve 27 such that the work implement 2 isactuated at a velocity in accordance with the aforementioned operatingamounts of the respective operating levers 28 and 29. Accordingly,outputs of the boom cylinder 10, the arm cylinder 11, the bucketcylinder 12, the revolving motor 24 and so forth are controlled inaccordance with the operating amounts of the respective operating levers28 and 29.

It should be noted that the control valve 27 may be a pressureproportional control valve. In this case, pilot pressures are configuredto be outputted from the boom operating portion 31, the bucket operatingportion 32, the arm operating portion 33 and the revolving motionoperating portion 34 in accordance with the operating amounts of therespective operating members, and are configured to be inputted into thecontrol valve 27. The control valve 27 is configured to control the flowrates of the hydraulic fluid to be supplied to the boom cylinder 10, thearm cylinder 11, the bucket cylinder 12 and the revolving motor 24 inaccordance with the pilot pressures inputted thereto. In this case, thepositional signals from the respective operating portions 31 to 34 maybe signals indicating the pilot pressures to be outputted from therespective operating portions 31 to 34.

The control system 300 includes a first stroke sensor 16, a secondstroke sensor 17 and a third stroke sensor 18. The first stroke sensor16 is configured to detect the stroke length of the boom cylinder 10(hereinafter referred to as “boom cylinder length”). The second strokesensor 17 is configured to detect the stroke length of the arm cylinder11 (hereinafter referred to as “arm cylinder length”). The third strokesensor 18 is configured to detect the stroke length of the bucketcylinder 12 (hereinafter referred to as “bucket cylinder length”). Anglesensors or so forth may be used for measuring the strokes.

The control system 300 includes a tilt angle sensor 19. The tilt anglesensor 19 is disposed in the revolving unit 3. The tilt angle sensor 19is configured to detect an angle (pitch) of the revolving unit 3relative to a horizontal plane arranged along the vehicle back-and-forthdirection and an angle (roll) of the revolving unit 3 relative to ahorizontal plane arranged along the vehicle transverse direction.

These sensors 16 to 19 are configured to transmit detection signals tothe controller 26. It should be noted that the revolving angles may beobtained based on positional information of a GNSS antenna 37 to bedescribed. The controller 26 is configured to determine the posture ofthe work implement 2 based on the detection signals from the sensors 16to 19.

The control system 300 includes a positional detector 36. The positionaldetector 36 is configured to detect the present position of the workvehicle 100. The positional detector 36 includes the GNSS antenna 37 anda three-dimensional position sensor 39. The GNSS antenna 37 is providedon the revolving unit 3. The GNSS antenna 37 is an antenna for RTK-GNSS(Real-Time Kinematic GNSS; GNSS refers to Global Navigation SatelliteSystems). A signal is configured to be inputted into thethree-dimensional position sensor 39 in accordance with GNSS radio wavesreceived by the GNSS antenna 37.

FIG. 3 is a side view of a schematic construction of the work vehicle100. The three-dimensional position sensor 39 is configured to detect aninstallation position P1 of the GNSS antenna 37 in a global coordinatesystem. The global coordinate system is a three dimensional coordinatesystem based on a reference position P2 set in a work area. As shown inFIG. 3, the reference position P2 is located in, for instance, the tipof a reference marker installed in the work area. The controller 26 isconfigured to compute the position of a cutting edge P4 of the workimplement 2 in the framework of the global coordinate system based onthe detection result by the positional detector 36 and the posture ofthe work implement 2. It should be noted that the cutting edge P4 of thework implement 2 may be expressed as the cutting edge P4 of the bucket8.

Based on a boom cylinder length detected by the first stroke sensor 16,the controller 26 is configured to calculate a tilt angle θ1 of the boom6 relative to a vertical direction in a local coordinate system. Basedon an arm cylinder length detected by the second stroke sensor 17, thecontroller 26 is configured to calculate a tilt angle θ2 of the arm 7relative to the boom 6. Based on a bucket cylinder length detected bythe third stroke sensor 18, the controller 26 is configured to calculatea tilt angle θ3 of the bucket 8 relative to the arm 7.

The storage unit 38 of the controller 26 stores work implement data. Thework implement data includes a length L1 of the boom 6, a length L2 ofthe arm 7 and a length L3 of the bucket 8. Additionally, the workimplement data includes information of the position of a boom pin 13relative to a reference position P3 in the local coordinate system.Here, the local coordinate system refers to a three dimensionalcoordinate system that is set based on the work vehicle 100. Thereference position P3 in the local coordinate system is located in, forinstance, the revolving center of the revolving unit 3.

The controller 26 is configured to calculate the position of the cuttingedge P4 in the local coordinate system based on the tilt angle θ1 of theboom 6, the tilt angle θ2 of the arm 7, the tilt angle θ3 of the bucket8, the length L1 of the boom 6, the length L2 of the arm 7, the lengthL3 of the bucket 8 and the positional information of the boom pin 13.

Additionally, the work implement data includes positional information ofthe installation position P1 of the GNSS antenna 37 relative to thereference position P3 in the local coordinate system. The controller 26is configured to convert the position of the cutting edge P4 in thelocal coordinate system into the position of the cutting edge P4 in theglobal coordinate system based on the detection result by the positionaldetector 36 and the positional information of the GNSS antenna 37.Accordingly, the controller 26 is configured to obtain the positionalinformation of the cutting edge P4 in the framework of the globalcoordinate system.

The storage unit 38 of the controller 26 stores construction workinformation indicating the shape and the position of a three-dimensionaldesigned terrain within the work area. FIG. 4 is a schematic diagram ofan exemplary designed terrain. As shown in FIG. 4, the designed terrainis constructed by a plurality of designed surfaces 41, each of which isexpressed by a polygon. The plural designed surfaces 41 respectivelyindicate a target shape of an excavation object by the work implement 2.It should be noted that in FIG. 4, a reference sign 41 is assigned toonly one of the plural designed surfaces 41 without being assigned tothe rest of the designed surfaces 41.

The controller 26 is configured to perform an automatic control of thework implement 2 in consideration of the designed surfaces 41. Theautomatic control includes controlling the work implement 2 such thatthe bucket 8 is prevented from eroding the designed surfaces 41. In theautomatic control, the controller 26 is configured to control the workimplement 2 based on the aforementioned construction work informationand the positional information of the work implement 2. The automaticcontrol of the work implement 2 means controlling the motion of the workimplement 2 by the controller 26 independently from controlling themotion of the work implement 2 based on an operational instruction bythe operator through the operating device 25. The automatic control ofthe work implement 2 includes a fully-automatic control and asemi-automatic control in performing a given work. The automatic controlof the work implement 2 to be performed by the controller 26 will behereinafter explained in detail.

FIG. 5 is a block diagram of a configuration of the controller 26. Thecomputation unit 35 of the controller 26 includes a distance obtainingportion 51, a work phase determining portion 52, an automaticallycontrolling portion 53 and a work implement controlling portion 54. Asshown in FIG. 6, the distance obtaining portion 51 is configured toobtain a distance dl between the work implement 2 and the designedsurfaces 41. When described in detail, the distance obtaining portion 51is configured to calculate the distance dl between the cutting edge P4of the work implement 2 and the designed surface 41 based on theaforementioned positional information of the cutting edge P4 of the workimplement 2 and the positional information of the designed surface 41.

The work phase determining portion 52 is configured to determine inwhich phase of work the work implement 2 is engaged. The work phasedetermining portion 52 is configured to determine in which phase of work(excavation, leveling, etc.) the work implement 2 is engaged based onthe aforementioned positional signals from the boom operating portion31, the arm operating portion 33 and the bucket operating portion 32.For example, when an arm operation is not being performed althougheither a boom operation or a bucket operation is being performed, thework phase determining portion 52 is configured to determine that thephase of work is excavation. When the arm operation is being performed,the work phase determining portion 52 is configured to determine thatthe phase of work is leveling.

When the phase of work is excavation, the automatically controllingportion 53 is configured to perform a velocity limiting control. In thevelocity limiting control, the automatically controlling portion 53 isconfigured to gradually limit the velocity of the work implement 2 inaccordance with reduction in the distance dl between the work implement2 and the designed surfaces 41. In other words, in the velocity limitingcontrol, the automatically controlling portion 53 is configured togradually lower the upper limit of the velocity of the work implement 2in accordance with reduction in the distance dl between the workimplement 2 and the designed surface 41. Accordingly, it is possible toinhibit occurrence of a situation that in excavation, the work implement2 excavates the earth across the designed surface 41.

When the phase of work is leveling, the automatically controllingportion 53 is configured to perform a leveling control. The levelingcontrol is a control for causing the work implement 2 to move along thedesigned surfaces 41. As shown in FIG. 7, when the cutting edge P4 ofthe work implement 2 is moved at a velocity V1 toward the designedsurface 41, the automatically controlling portion 53 is configured tocalculate a velocity component V1 a of the velocity V1 that isperpendicular to the designed surface 41. The automatically controllingportion 53 is configured to determine a velocity at which the boom 6 iselevated whereby the perpendicular velocity component V1 a is canceledout. Accordingly, the work implement 2 is controlled by the levelingcontrol such that the cutting edge P4 can be moved along the designedsurface 41.

The work implement controlling portion 54 is configured to output acommand signal to the aforementioned control valve 27 so as to controlthe work implement 2. The work implement controlling portion 54 isconfigured to determine an output value of the command signal to beoutputted to the control valve 27 in accordance with the operatingamount of the work implement 2. Additionally, during performing theautomatic control, the work implement controlling portion 54 isconfigured to determine the output value of the command signal to beoutputted to the control valve 27 based on the velocity of the workimplement 2 determined by the automatically controlling portion 53.

As shown in FIG. 2, the control system 300 includes a display unit 40.The display unit 40 is a monitor, for instance, and is configured todisplay information regarding the work vehicle 100. The controller 26 isconfigured to cause the display unit 40 to display a guidance screenbased on a designed terrain and detection results from theaforementioned various sensors. FIG. 8 is a diagram showing an exampleof a guidance screen 61. As shown in FIG. 8, the guidance screen 61shows a positional relation between the designed surfaces 41 and thework implement 2.

When described in detail, the guidance screen 61 includes a firstguidance screen 62 and a second guidance screen 63. The first guidancescreen 62 shows the designed surface 41 and the work implement 2 in theform of a side view. The second guidance screen 63 shows the designedsurface 41 and the work implement 2 in the form of a perspective view.The guidance screen 61 includes a distance indicator 65 indicating thedistance between the work implement 2 and the designed surface 41. Itshould be noted that one of the first and second guidance screens 62 and63 may not be provided.

As shown in FIG. 2, the control system 300 includes an input unit 42.The input unit 42 is a device for inputting settings of theaforementioned automatic control. The operator is capable of changingthe settings of the automatic control by operating the input unit 42. Inthe present exemplary embodiment, the input unit 42 is a touch paneldevice provided integrally with the display unit 40. It should be notedthat the input unit 42 may be provided separately from the display unit40.

Next, operating the automatic control by the first and second operatinglevers 28 and 29 will be explained in detail. FIG. 9A is a front view ofthe first operating lever 28. FIG. 9B is a side view of the firstoperating lever 28. As shown in FIGS. 9A and 9B, the first operatinglever 28 is provided with a plurality of operating members A1, A2, A3,A4 and A5. The operating members A1, A2, A3 and A4 are mounted to thefront surface of the first operating lever 28. The operating members A1,A2, A3 and A4 are mounted to the upper portion of the first operatinglever 28. The operating member A5 is mounted to the rear surface of thefirst operating lever 28.

The operating members A1, A2 and A3 are switches of a push button type.An operating signal, which indicates a push-on state or a push-off stateof each operating member A1, A2, A3 is inputted to the controller 26from each operating member A1, A2, A3. The operating member A4 is aswitch of a slide type or a rotary type. An operating signal, whichcorresponds to the operating position of the operating member A4, isinputted to the controller 26 from the operating member A4. Theoperating member A5 is a switch of a trigger type. An operating signal,which indicates a push-on state or a push-off state of the operatingmember A5, is inputted to the controller 26 from the operating memberA5.

FIG. 10A is a front view of the second operating lever 29. FIG. 10B is aside view of the second operating lever 29. As shown in FIGS. 10A and10B, the second operating lever 29 is provided with a plurality ofoperating members B1, B2, B3, B4 and B5. The operating members B1, B2,B3 and B4 are mounted to the front surface of the second operating lever29. The operating members B1, B2, B3 and B4 are mounted to the upperportion of the second operating lever 29. The operating member B5 ismounted to the rear surface of the second operating lever 29.

The operating members B1, B2 and B3 are switches of a push button type.An operating signal, which indicates a push-on state or a push-off stateof each operating member B1, B2, B3 is inputted to the controller 26from each operating member B1, B2, B3. The operating member B4 is aswitch of a slide type or a rotary type. An operating signal, whichcorresponds to the operating position of the operating member B4 isinputted to the controller 26 from the operating member B4. Theoperating member B5 is a switch of a trigger type. An operating signal,which indicates a push-on state or a push-off state of the operatingmember B5, is inputted to the controller 26 from the operating memberB5.

Functions of the automatic control are allocated to portion of theseoperating members A1-A5 and B1-B5. In the present exemplary embodiment,functions of the automatic control are allocated to the operatingmembers A2, B2 and A5.

It should be noted that operations related to the work implement 2 andthose related to the vehicle body 1 are allocated to the operatingmembers other than the operating members A2, B2 and A5. The operationsrelated to the work implement 2 include, for instance, an operation of awork tool such as a breaker that is employed instead of the bucket 8 andis attached to the work implement 2. The operations related to thevehicle body 1 include, for instance, an operation to increase engineoutput, an operation to blow a horn, and so forth.

When described in detail, a function of elevating the position of thedesigned surfaces 41 is allocated to the operating member A2. Theposition of the designed surface 41 is configured to be changed upwardin response to the operation of the operating member A2. In response toa single operation of the operating member A2, the position of thedesigned surface 41 is configured to be changed upward by apredetermined distance.

FIG. 11 shows a condition that as a result of pressing the operatingmember A2 once, the designed surface 41 has been moved upward from itsinitial position (see FIG. 8) by the predetermined distance in theguidance screen 61. FIG. 12 shows a condition that as a result ofpressing the operating member A2 once again, the designed surface 41 hasbeen moved further upward by the predetermined distance in the guidancescreen 61.

A function of lowering the position of the designed surface 41 isallocated to the operating member B2. The position of the designedsurface 41 is configured to be changed downward in response to theoperation of the operating member B2. In response to a single operationof the operating member B2, the position of the designed surface 41 isconfigured to be changed downward by the predetermined distance. FIG. 13shows a condition that as a result of pressing the operating member B2once, the designed surface 41 has been moved downward from its initialposition (see FIG. 8) by the predetermined distance in the guidancescreen 61. FIG. 14 shows a condition that as a result of pressing theoperating member B2 once again, the designed surface 41 has been movedfurther downward by the predetermined distance in the guidance screen61.

As described above, when the operating member A2 or B2 is operated, theposition of the designed surface 41 is configured to be changed upwardor downward in the guidance screen 61. Then, the aforementionedautomatic control is configured to be performed based on the changedposition of the designed surface 41. It should be noted that theaforementioned predetermined distance may be changeable by operating theinput unit 42. Alternatively, the aforementioned predetermined distancemay be a fixed value.

A function of enabling/disabling the automatic control is allocated tothe operating member A5. Every time the operating member A5 is operated,enabling and disabling the automatic control are configured to bealternately switched. Enabling the automatic control means that theautomatic control is allowed to be performed. Disabling the automaticcontrol means that the automatic control is not allowed to be performedand the operating mode of the work implement 2 is set to a manual modein which the work implement 2 is manually operated.

As described above, the operator is capable of causing the functions ofthe automatic control, which are respectively allocated to the operatingmembers A2, B2 and A5, to be performed by operating the operatingmembers A2, B2 and A5. It should be noted that the controller 26 isconfigured to perform the functions of the automatic control, which arerespectively allocated to the operating members A2, B2 and A5, when aperformance condition is satisfied.

The performance condition is a condition that the operating levers arenot being operated by the operator to actuate the work implement 2. Inthe present exemplary embodiment, the performance condition is acondition that the first operating lever 28 is located in its neutralposition and simultaneously the second operating lever 29 is located inits neutral position. Therefore, the position of the designed surface 41is configured to be moved upward by operating the operating member A2when both of the first and second operating levers 28 and 29 are locatedin their neutral positions. The position of the designed surface 41 isconfigured to be moved downward by operating the operating member B2when both of the first and second operating levers 28 and 29 are locatedin their neutral positions. Even when either of the operating members A2and B2 is operated, the position of the designed surface 41 isconfigured not to be changed as long as at least either of the first andsecond operating levers 28 and 29 has been operated and is located in adifferent position from its neutral position.

On the other hand, the automatic control is configured to be switchedfrom enabled to disabled or vice versa by operating the operating memberA5 when both of the first and second operating levers 28 and 29 arelocated in their neutral positions. Even when the operating member A5 isoperated, the automatic control is configured not to be switched fromenabled to disabled or vice versa as long as at least either of thefirst and second operating levers 28 and 29 has been operated and islocated in a different position from its neutral position.

FIG. 15 is a flowchart showing a series of processing steps to beperformed in operating any of the operating members A2, B2 and A5. Asituation that the operating member A2 has been operated will be hereinexplained as an example.

As shown in FIG. 15, in Step S1, an operation of the operating member A2is detected. Here, the controller 26 detects the operation of theoperating member A2 when receiving the operating signal from theoperating member A2.

In Step S2, the positions of the operating levers 28 and 29 aredetected. Here, the controller 26 detects the position of the firstoperating lever 28 when receiving the positional signal indicating theposition of the first operating lever 28 from the operating device 25.Likewise, the controller 26 detects the position of the second operatinglever 29 when receiving the positional signal indicating the position ofthe second operating lever 29 from the operating device 25.

In Step S3, it is determined whether or not the performance condition issatisfied. Here, the controller 26 determines whether or not the firstoperating lever 28 is located in its neutral position and simultaneouslythe second operating lever 29 is located in its neutral position. Whenboth of the first and second operating levers 28 and 29 are located intheir neutral positions, the controller 26 determines that theperformance condition is satisfied. When at least either of the firstand second operating levers 28 and 29 is located in a different positionfrom its neutral position, the controller 26 determines that theperformance condition is not satisfied.

When the performance condition is satisfied, the function allocated tothe operating member A2 is performed in Step S4. Here, the controller 26is configured to change the position of the designed surfaces 41 upward.Even when the operating member A2 is operated, the function of theoperating member A2 is configured not to be performed as long as theperformance condition has not been satisfied. In other words, even whenthe operating member A2 is operated, the position of the designedsurface 41 is configured not to be changed as long as the performancecondition has not been satisfied.

It should be noted that when the operating member B2 is operated, theposition of the designed surface 41 is moved downward in Step S4. Whenthe operating member A5 is operated, the automatic control is switchedfrom enabled to disabled or vice versa in Step S4. It should be notedthat the functions allocated to the operating members A2, B2 and A5 arealso operable through the input unit 42.

In the control system 300 of the work vehicle 100 according to thepresent exemplary embodiment explained above, the first operating lever28 is provided with the operating members A2 and A5. With theconstruction, the operator is capable of operating the operating membersA2 and A5 while holding the first operating lever 28. Accordingly, thefunctions of the automatic control, which is allocated to the operatingmembers A2 and A5, can be easily operated. Likewise, the secondoperating lever 29 is provided with the operating member B2. With theconstruction, the operator can operate the operating member B2 whileholding the second operating lever 29. Accordingly, the function of theautomatic control, which is allocated to the operating member B2, can beeasily operated.

Specifically, the operator can change the position of the designedsurfaces 41 upward and downward by operating the operating members A2and B2 while holding the first and second operating levers 28 and 29.Additionally, the operator can switch the automatic control from enabledto disabled or vice versa by operating the operating member A5 whileholding the first operating lever 28.

Moreover, even when the operating members A2, B2 and A5 are operated,the functions of the automatic control, which are respectively allocatedto the operating members A2, B2 and A5, are configured not to beperformed as long as at least either of the first and second operatinglevers 28 and 29 is located in a different position from its neutralposition. Because of the configuration, even when either of the firstand second operating levers 28 and 29 is moved during operating theoperating members A2, B2 and A5, it is possible to simultaneouslyprevent performing the functions of the automatic control, which arerespectively allocated to the operating members A2, B2 and A5, andprevent actuating the work implement 2 by operating either of the firstand second operating levers 28 and 29. Accordingly, it is possible toprevent occurrence of an unintentional motion of the work implement 2attributed to an erroneous operation and perform a construction workwith good quality by the automatic control.

One exemplary embodiment of the present invention has been describedabove. However, the present invention is not limited to theaforementioned exemplary embodiment, and a variety of changes can bemade without departing from the scope of the present invention.

The work vehicle 100 is not limited to the hydraulic excavator, and maybe any type of vehicle (e.g., bulldozer, wheel loader, etc.) as long asit is provided with a work implement.

The work vehicle 100 may be configured to be remotely controllable.Specifically, the controller 26 may be divided into a remote controllerdisposed outside the work vehicle 100 and an in-vehicle embeddedcontroller disposed inside the work vehicle 100, and the remotecontroller and the in-vehicle embedded controller may be configured tobe capable of communicating with each other.

The method of determining the position of the cutting edge P4 of thework implement 2 is not limited to that of the aforementioned exemplaryembodiment, and may be changed. For example, the positional detector 36may be disposed on the cutting edge P4 of the work implement 2.

The method of detecting the distance dl between the work implement 2 andthe designed surfaces 41 is not limited to that of the aforementionedexemplary embodiment, and may be changed. For example, the distance dlbetween the work implement 2 and the designed surface 41 may be detectedby an optical distance meter, an ultrasonic distance meter or a laserdistance meter.

Conditions to be satisfied for performing the functions of the automaticcontrol in accordance with operating the operating members A2, B2 and A5may be set differently from each other. For example, the condition(first performance condition) to be satisfied in operating the operatingmembers A2 and A5 of the first operating lever 28 may include that thefirst operating lever 28 is located in the neutral condition but may notinclude that the second operating lever 29 is located in the neutralposition. On the other hand, the condition (second performancecondition) to be satisfied in operating the operating member B2 of thesecond operating lever 29 may include that the second operating lever 29is located in the neutral position and may not include that the firstoperating lever 28 is located in the neutral position.

In the aforementioned exemplary embodiment, the operating member A2(first operating member) for changing the position of the designedsurfaces 41 upward and the operating member B2 (second operating member)for changing the position of the designed surface 41 downward arerespectively provided for the different operating levers 28 and 29.However, the operating members A2 and B2 may be provided for the sameoperating lever. Alternatively, the function of changing the position ofthe designed surface 41 upward and downward may be allocated to anoperating member designed to be operable up and down such as theoperating member A4 or the operating member B4.

The constructions of the first and second operating levers 28 and 29 maybe changed. The number, positional arrangements or shapes of theoperating members provided for the first operating lever 28 and that orthose of the operating members provided for the second operating lever29 may be changed. The operating members to which the functions of theautomatic control are allocated are not limited to the operating membersA2, B2 and A5, and may be the other operating members.

The functions of the automatic control to which the operating membersare allocated are not limited to changing the position of the designedsurfaces 41 and switching the automatic control from enabled to disabledor vice versa, and may be the other functions. It is preferable toallocate a frequently used function of the automatic control to anoperating member. For example, as shown in FIG. 16, the automaticcontrol may include an angle maintaining control for maintainingconstant an angle An of the bucket 8 relative to the designed surface 41in the leveling control. Switching the angle maintaining control fromenabled to disabled or vice versa may be allocated to the operatingmember.

A function of selecting a specific one of the plural designed surfaces41 may be allocated to an operating member. For example, as shown inFIG. 17, a function of selecting a designed surface 41 a locatedimmediately below the cutting edge P4 may be allocated to the operatingmember. The aforementioned automatic control may be configured to beperformed based on the selected designed surface 41 a. Alternatively,the selected designed surface 41 a may be configured to be displayedwith a different aspect (e.g., different color) from the other designedsurfaces 41. Alternatively, the guidance screen 61 may be configured todisplay whether or not the work vehicle 100 faces to the selecteddesigned surface 41 a. FIG. 17 shows that the guidance screen 61displays whether or not the work vehicle 100 faces to the selecteddesigned surface 41 a with a compass icon 64.

A function of changing display scaling in the guidance screen 61 may beallocated to an operating member. For example, a function of switchingbetween the guidance screen 16 taking the form of schematic display asshown in FIG. 17 and a guidance screen 61′ taking the form of detaildisplay as shown in FIG. 18 may be allocated to the operating members.The designed surfaces 41 and 41 a may be configured to be displayed withlarger sizes in the detailed display shown in FIG. 18 than in theschematic display shown in FIG. 17. Additionally, in the schematicdisplay shown in FIG. 17, the entirety of the work vehicle 100 may beconfigured to be displayed on the guidance screen 61. Compared to this,in the detailed display shown in FIG. 18, only the bucket 8 may bedisplayed with a larger scale on the guidance screen 61′ than in theschematic display.

The conditions to be satisfied for performing the functions of theautomatic control in accordance with operating the predeterminedoperating members may further include operating the other operatingmember different from the predetermined operating members. For example,one of the functions of the automatic control may be configured to beperformed by operating the operating member A2 in a condition that thefirst operating lever 28 is located in the neutral position andsimultaneously the operating member A4 is being operated. Alternatively,one of the functions of the automatic control may be configured to beperformed by operating the operating member B2 in a condition that thesecond operating lever 29 is located in the neutral position andsimultaneously the operating member B4 is being operated.

Alternatively, a predetermined function (first function) of theautomatic control may be configured to be performed by operating theoperating member A2 in a condition that the first operating lever 28 islocated in the neutral position and simultaneously the operating memberA4 is not being operated. Moreover, a predetermined function (thirdfunction) of the automatic control, which is different from the firstfunction, may be configured to be performed by operating the operatingmember A2 in a condition that the second operating lever 29 is locatedin the neutral position and simultaneously the operating member A4 isbeing operated.

For example, the first function may be a function of changing theposition of the aforementioned designed surface 41 upward or downward.The third function may be a function of selecting the designed surface41 from the plural designed surfaces 41. Alternatively, the thirdfunction may be a function of changing the display scaling in theguidance screen 61. The first and third functions may be respectivelydifferent from those described above.

Conditions included in the aforementioned performance condition may bechanged. Alternatively, conditions different from those described abovemay be added to the conditions included in the performance condition.The performance condition is not limited to that the operating leversare located in their neutral positions, and may include anothercondition indicating that the operating levers are not being operated bythe operator.

According to the present invention, it is possible to easily operate afunction of an automatic control, prevent occurrence of an unintentionalmotion of a work implement attributed to an erroneous operation, andperform a construction work with good quality by the automatic control.

What is claimed is:
 1. A control system for a work vehicle including awork implement, the control system comprising a first operating leverfor the work implement; a first operating member provided on the firstoperating lever; and a controller programmed to control the workimplement based on a designed terrain indicating a target shape of awork object, the controller being configured to change a position of thedesigned terrain in response to an operation of the first operatingmember when a performance condition is satisfied, the performancecondition including the first operating lever being located in a neutralposition.
 2. The control system according to claim 1, wherein thecontroller is configured to change the position of the designed terrainby a predetermined distance in response to the operation of the firstoperating member.
 3. The control system according to claim 2, whereinthe controller is configured to change the position of the designedterrain by the predetermined distance once each time the first operatingmember is operated.
 4. The control system according to claim 2, furthercomprising an input device connected to the controller, the controllerbeing configured to change the predetermined distance in response to anoperation of the input device.
 5. The control system according to claim2, wherein the predetermined distance is a fixed value.
 6. The controlsystem according to claim 1, further comprising a second operatingmember, the controller being configured to change the position of thedesigned terrain in response to an operation of the second operatingmember when the performance condition is satisfied, the change of theposition of the designed terrain in response to the operation of thesecond operating member being different from the change of the designedterrain in response to the operation of the first operating member, thecontroller being configured to change the position of the designedterrain upward in response to the operation of the first operatingmember and downward in response to an operation of the second operatingmember.
 7. The control system according to claim 6, wherein thecontroller is configured to change the position of the designed terrainupward by a predetermined distance in response to the operation of thefirst operating member, and the controller is configured to change theposition of the designed terrain downward by the predetermined distancein response to the operation of the second operating member.
 8. Thecontrol system according to claim 6, wherein the second operating memberis provided on the first operating lever.
 9. The control systemaccording to claim 6, further comprising a second operating lever, thesecond operating member being provided on the second operating lever,the performance condition further including the second operating leverbeing located in a neutral position.
 10. A method of controlling a workvehicle having a work implement, the method comprising the steps of:receiving a positional signal indicating a position of a first operatinglever for the work implement; receiving an operating signal indicatingoperation of a first operating member provided on the first operatinglever; determining whether or not a performance condition is satisfied,the performance condition including the first operating lever beinglocated in a neutral position; and changing a position of a designedterrain in response to receiving the operating signal when theperformance condition is satisfied, the designed terrain indicating atarget shape of a work object.
 11. A work vehicle, comprising: workimplement; a first operating lever for the work implement; a firstoperating member provided on the first operating lever; and a controllerprogrammed to control the work implement based on a designed terrainindicating a target shape of a work object, the controller beingconfigured to change a position of the designed terrain in response toan operation of the first operating member when a performance conditionis satisfied, the performance condition including the first operatinglever being located in a neutral position.